ask the labs
AR Solutions
Susan Tarrant
Though most of the issues associated with AR’s early years have been solved, some issues remain regarding crazing. Here, we discuss what ECPs and patients can do to help alleviate AR problems, with information provided by iCoat Company, a full-service lab in Santa Fe Springs, CA.
EDGING
If edging in-office, proper care must be taken to use the correct blocks and leap pads. The blocks should be as large as possible, have solid centers, and match the base curve of the lens as closely as possible. Leap pads should be of the highest quality adhesive to insure a strong grip.
Also, make sure blocking chucks on the edger are the same size for the front and the back of the lens. If they are not, lenses will experience uneven pressure and flex, potentially causing crazing of the coatings.
Extra care should also be taken while edging thin-center polycarbonate lenses, as they are soft in nature and can easily flex under too much pressure, causing crazing.
ARTIFICIAL AND NATURAL HEAT
Mounting lenses or adjusting frames with heat is another area in which the potential for crazing of the AR coating exists. Because most lens materials are made of plastic substrates, they are more susceptible to expansion and contraction with changes in temperature. And, as most AR coatings are quartz based, they don’t expand or contract like plastic-based lens materials. This expansion and contraction can cause crazing or cracking.
When adjusting frames using a hot air blower or hot salt/bead pan, remove the lenses from the frame prior to exposing to heat; reinsert after adjustments have been made.
| Patient Ed |
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The key to patient satisfaction with AR is proper lens care. Don’t skimp on the care instructions or you could be faced with returns or unhappy customers. Provide all AR wearers with the following cleaning tips: ■ Avoid the use of household chemicals, soaps with creams, or tissues with lotion to wipe AR lenses. ■ Clean daily using water or a recommended AR cleaner. ■ Use only a soft cotton or microfiber cloth (preferably the one you supply them with). No shirttails! |
No matter how high quality a premium AR coating is, excess exposure to a high heat source can lead to crazing and early deterioration of the lens and coating.
Patients need to be educated on proper care of their eyewear, including the fact that they should never leave eyewear on an automobile dashboard on hot, sunny days; and should store the eyewear only in a protective case when not in use. EB
If you have a question you’d like to have answered in Ask the Labs, send it to Susan Tarrant. Email: Susan.Tarrant@PentaVisionMedia.com. An archive of past Ask the Labs columns can be found on the Eyecare Business Website at eyecarebusiness.com.
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